A human's eye is able to see fine detail in only a small sliver of its visual field. However, the mind uses saccades (quick, automatic eye movements) to compensate for this weakness. The eye performs two or three saccades each second to give the mind a single, seamless whole. When a person is severely drunk, the saccades slow down, and the mind begins to see the world as the eye perceives it, a patch of sharpness surrounded by a blurry field.